The present invention relates to a radial piston pump of the kind having pistons in their cylinder in radial arrangement about an axis.
With regard to the drive of the pistons, the pump of the above kind is of the positive-drive type, in which the driving shaft has an eccentric carrying a cam with which the spring loaded pistons are held in contact, so that the cam at each rotation of the driving shaft produces the reciprocating movement of the pistons in their respective cylinders.
The compression chamber of each cylinder receives liquid through the piston inner chamber. The piston inner chamber of each piston receives the liquid through inlet openings in the wall of the piston with the piston in the suction stroke. With the piston in the subsequent compression stroke, there occurs a surge pressure in each piston upon or immediately after closure of the inlet openings. This surge pressure causes vibration and noise of the pump.
An object of the present invention is to decrease the surge pressure in each piston of the pump of the above kind.